May 19, 2008
PET Infusion System Seeks to Simplify FDG Delivery
By Dan Harvey
Vol. 9 No. 10 P. 7
Seeking to improve fluid control in molecular imaging studies, MEDRAD of Warrendale, Pa., has developed the investigational Intego PET Infusion System to enable users to better control the delivery of fluorodeoxyglucose (FDG) for PET exams. At press time, MEDRAD had applied for FDA 510(k) clearance and was hoping for approval by the beginning of this month.
The company’s intent is to provide a safe, precise, and cost-effective system that reduces manual handling and increases FDG dose-injection accuracy, enabling facilities to provide more consistent image acquisition while reducing radiation exposure to technologists. The system’s tungsten-shielded FDG dose vials and lead-lined box on wheels cut exposure by as much as 40%.
“Technologists receive radiation from FDG preparation and handling and from the patients themselves who become radioactive once injected. There is nothing we can do about that, but we can remove the vast majority of the dose technologists receive during handling and preparation,” says Alan Connor, MEDRAD’s director of global marketing for molecular imaging.
The new system replaces syringe-based unit doses with shielded dose vials. “With the current method, facilities order doses according to patient schedule, and the radiopharmacy prepares the doses in syringes,” explains Connor. “Technologists then assay the syringes, modifying dose as necessary, and deliver the dose via injection.”
The Intego system automates much of the manual handling. Technologists place the shielded vial containing FDG into the power injector system and, instead of manually calibrating the doses, use a touch screen interface to enter the assay information to gauge the activity in the vial at a certain time.
“Manual dose adjustment can be quite challenging,” Connor says. “It’s generally accepted that manual delivery falls within plus or minus 10% of the prescribed dose. Intego delivers a much more accurate dose, and this translates into lower radiation doses for both the patient and technologist.”
The injector system accurately delivers prescribed patient doses anytime throughout the day and tracks radioactivity in the vial as it decays to verify how much activity remains available.
Individual doses are measured by an integrated dose calibration function. Before injection, the system automatically takes the assay information and calculates how much volume it needs to hit the prescribed dose. The system extracts two slugs of FDG from the vial until it reaches the exact prescribed amount. The technologist then presses the inject button to push the entire slug into the patient via a saline flush. The injector also has a weight-based calculation that lets technologists enter a formula, allowing the system to calculate the dose.
“Everything happens within the system,” explains Connor. “The system draws the fluid from the vial and users enter the prescribed dose into the system, which then prepares the dose and injects it right at the patient’s bedside. The technologist never has to touch, adjust, or measure the radioactive material.”
Besides this potential safety advantage, the system’s more precise dose and reduction of imaging variables are crucial when staging cancer. Facilities can also benefit economically from decreased delivery charges associated with FDG and less time spent in the lab to coordinate dosing, a significant consideration for higher volume sites.
In addition, Connor says the system provides facilities with scheduling flexibility. “Schedule management related to FDG supply is a huge challenge,” he adds. “As radioactivity constantly decays, alignment must be constant—but decay is uncontrollable. As such, schedule disruptions, such as late arrivals and cancellations, create havoc with a provider’s ability to service patients and get the needed FDG. But as long as there is enough radioactivity remaining in the system, you can deliver a dose at any time. Intego makes that possible.”
Pending FDA approval, MEDRAD will introduce Intego at the Society of Nuclear Medicine annual meeting later this month in New Orleans. “Once we receive approval, we’ll start taking orders and begin delivering products this summer,” says Connor.
While the approval process didn’t require MEDRAD to conduct clinical trials, the company worked with clinicians and technologists at the Cleveland Clinic and the University of Pittsburgh Medical Center throughout product development to test the system.
A Swiss physician first developed the concept of the PET infusion system and then approached MEDRAD. The company is now collaborating with three major FDG suppliers (PETNET Solutions, IBA Molecular, and Cardinal Health) to develop future imaging products. Connor says a SPECT agent delivery system is in early development stages and should be ready in two to three years.
— Dan Harvey is a freelance writer based in Wilmington, Del., and a frequent contributor to Radiology Today.